Set default unit for new items

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals a key behavioral trait: the tool does not influence MCP-added items, only the lighterpack.com UI default. This is important context that goes beyond the name. It doesn't mention return values or persistence, but for a simple setter, the main behavior is transparent.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no wasted words. It front-loads the core purpose and then adds a concise scope clarification. Every sentence earns its place, and the structure is easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter setter with no output schema, the description is nearly complete. It explains the tool's effect and its limitation regarding MCP-added items. There is slight ambiguity about whether the setting is list-wide or global, but this is a minor gap and does not significantly hinder correct usage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has no descriptions (0% coverage), so the description must compensate. It clarifies that the 'unit' parameter is the default unit for new items in the UI, adding semantic meaning beyond the raw enum in the schema. The allowed values (oz, lb, g, kg) are self-explanatory, and the description confirms their role.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool sets the default unit that LighterPack's UI pre-fills for new items. It distinguishes itself from the MCP flow by noting that MCP-added items always take an explicit weight_unit, and the tool only affects lighterpack.com's UI. This makes the purpose specific and separates it from siblings like set_total_unit.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear usage context by explicitly stating that items added through this MCP server always take an explicit weight_unit per call, so this tool only affects the web UI's pre-fill. This tells the agent when to use it and when not to, though it doesn't name alternative tools explicitly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.